The Cardiovascular System

Question 1

what are the components involved in the regulation of blood circulation?

Answer 1

Brain

Kidneys (adrenal glands)

Question 2

what’s the function of the cardiovascular system?

Answer 2

enables an adequate supply of blood to tissues, supplying nutrients, signal molecules and waste products

Question 3

what must blood supply be depending on the needs or the organs/tissues (physiological demands)?

Answer 3

adaptable

Question 4

why must there be an establishment of pressure differentials across tissues?

Answer 4

for capillary exchange

Question 5

what is haemodynamics?

Answer 5

the physics of blood flow

Question 6

what letter indicates the flow of blood?

Answer 6

F

Question 7

what letter denotes resistance?

Answer 7

R

Question 8

what letter denotes pressure difference (between point A and B)?

Answer 8

P

Question 9

what’s Darcy’s law?

Answer 9

F= difference in P/ difference in R

Question 10

what 3 factors is R (resistance) affected by?

Answer 10

length of vessel (L)
radius of vessel (r)
fluid viscosity (n)

Question 11

if blood is lower in protein is it more or less viscous?

Answer 11

lless (blood flows more freely)

Question 12

what’s the equation to calculate resistance?

Answer 12

R= 8Ln/pi r^4

Question 13

what is resistance proportional to?

Answer 13

1/r^4

Question 14

by combining Darcy’s law and the equation for Resistance how is F calculated?

Answer 14

F= difference in P x pi r^4/8Ln

Question 15

what is Flow proportional to?

Answer 15

r^4

Question 16

How does a smaller radius affect resistance?

Answer 16

more blood in contact with wall therefore more resistance so reduced flow

Question 17

order these by diameter: Elastic arteries, muscular arteries and arterioles (largest to smallest)

Answer 17

elastic arteries, muscular arteries, arterioles

Question 18

order these by the rate of blood flow: Elastic arteries, muscular arteries and arterioles (highest to lowest)

Answer 18

elastic arteries, muscular arteries, arterioles

Question 19

what is the pressure gradient (difference in P) determined by?

Answer 19

contraction of heart muscle

Question 20

are there differences in intra-cardiac pressure (between each valve)?

Answer 20

yes

Question 21

what’s the technical term for contraction?

Answer 21

systole

Question 22

what’s the technical term for relaxation?

Answer 22

diastole

Question 23

what’s the pressure in the left ventricle at contraction/systole? (mmHg)

Answer 23

100-140

Question 24

what’s the pressure in the left ventricle at relaxation/diastole? (mmHg)

Answer 24

3-12

Question 25

what's the pressure in the right atria during contraction/systole?(mmHg)

Answer 25

6-12

Question 26

what's the pressure in the right ventricle during relaxation/diastole? (mmHg)

Answer 26

3-8

Question 27

what's the pressure in the right atria during contraction/systole? (mmHg)

Answer 27

2-6

Question 28

why is the left of the heart under higher pressure than the right?

Answer 28

higher pressure is required for peripheral circulation than pulmonary

Question 29

what's ideal blood pressure?

Answer 29

110/70

Question 30

what's the issue with having an ideal blood pressure?

Answer 30

it changes with age and other factors

Question 31

how does blood pressure appear on a graph?

Answer 31

a wave

Question 32

what's happening on a blood pressure graph as the wave rises?

Answer 32

systole

Question 33

what's happening on a blood pressure graph as the wave falls?

Answer 33

diastole

Question 34

why's there are notch between systole and diastole on a blood pressure graph?

Answer 34

valves are closing

Question 35

how is mean arterial pressure calculated?

Answer 35

mean arterial pressure= 1/3 pulse pressure (difference between systole and diastole)/ diastolic pressure

Question 36

what 3 components are considered looking at the cardiac cycle?

Answer 36

electrical events mechanical events electro-mechanical contraction coupling (ECG)

Question 37

what's the conduction pathway?

Answer 37

SAN-->atrial myocardium --> AV node --> Bundle of His--> Purkinje network --> ventricular myocardium

Question 38

at what speed is the electrical signal from the atria to atrioventricular node?

Answer 38

1 m/s

Question 39

what speed is the electrical signal from atrioventricular node to bundles of His?

Answer 39

0.05m/s

Question 40

what speed is the electrical signal from bundles of His to ventricular myocardium (along the purkinje fibres)?

Answer 40

1 m/s

Question 41

what regulates the heart's electrical impulse?

Answer 41

SAN, AVN and BoH

Question 42

during most of the cardiac cycle are the atria and ventricles relaxed or contracting?

Answer 42

relaxed (allowing blood to fill the heart)

Question 43

what is an ECG?

Answer 43

a devise where sensors are places externally on the body, which produces an ECG trace to detect the action potential throughout the cardiac cycle

Question 44

what does the P-wave show on an ECG trace?

Answer 44

atrial depolarization, therefore contraction

Question 45

what does the QRS complex show on an ECG trace?

Answer 45

spread of electrical signal associated with ventricular contraction. Atria are relaxing which is masked by the larger ventricular contraction event

Question 46

what does the T-wave show on an ECG trace?

Answer 46

ventricle repolarization/relaxation (atria are also contracting which is masked by ventricular activity)

Question 47

why is the T-wave positive?

Answer 47

it shows repolarization

Question 48

what is the Q-T interval?

Answer 48

time from the initiation of ventricular contraction to the end of ventricular relaxation